A conventional padlock with either a key locking device or a combination locking device is popular because the padlock with a single locking device is easy to use and such a padlock is provided for individual use only. Generally, travelers would apply different padlocks to lock their luggage so as to protect their personal items. Therefore, authorized security staff would have great difficulties in opening the luggage and checking the personal items due to safety concerns, if the luggage were locked by the padlocks with the single locking devices.
Furthermore, another conventional padlock with dual locking devices, namely with a key and a combination locking devices, is also well-known for satisfying the safety concerns. Substantially, the padlock with the dual locking devices is provided for both individual and security authorities uses. Accordingly, the individual is capable of locking or unlocking their luggage by using one locking device of the padlock, namely the combination locking device, to protect their personal items, and the security authorities are capable of unlocking or locking the luggage by using the other locking device, namely the key locking device, during safety inspections. Thus, the padlock with dual locking devices advantages both the individual and the security authorities.
Because the padlocks with the dual locking devices have greater advantages over the padlocks with the single locking device that would gain a great attention to the public and the authorities, and such padlocks having strong structures and easy operating characteristics are in a great demand.